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By B. Hilscher, P. Nayak, N. Yoon

"The mining industry is currently facing challenges with declining feed grades and is struggling to find solutions to improve the project’s economic value. By means of pre-concentration, ore sorting aims to separate the barren material from the valuable ore to reduce energy consumption and tailings generation, while increasing the feed grade, concentrate grade, mill recovery, and revenue. In addition, ore sorting allows the modification of deposit geometallurgy in order to allow the creation of an optimal mill feed.This paper evaluates the applicability and challenges of ore sorting by utilizing the results from four different mines, and reviews them in detail. The mines include two underground and two open pit mines that are base metal and precioius metal operations. In order to understand the applicability of ore sorting in these operations, initial rock-by-rock test results and different types of assays (atomic adsorption [AA], inductively coupled plasma [ICP], and fire assay) are utilized. Using the assay results, the grade recovery curves for ore sorting are generated and they are further improved by using and developing an ore sorting algorithm, which is discussed in this paper. The application and evaluation of ore sorting in greenfield and brownfield properties will also be discussed.The state of the art ore sorting technologies for both rock-by-rock and bulk sorting are reviewed in this paper. The future technologies on the horizon, including different combinations of sensors, are explained. The sorting technologies include, X-ray transmission (XRT), X-ray fluorescence (XRF), colour, infrared, electromagnetic, and laser induced breakdown spectroscopy (LIBS).IntroductionOre sorting is a sensor-based sorting technique introduced between the excavation stage and processing stage, where the unwanted waste is diverted to the waste dump and only the ore is sent to the mill for further processing. As a result, the quality of the material entering the mill is improved and the dilution of the ore is reduced. In greenfield projects, sensor-based ore sorting provides an opportunity to reduce the capital cost of the project and increase the return on investment (ROI). With most operations currently facing the challenge of finding a high grade deposit, having a sorting unit provides several advantages while keeping the cost at minimum."

Jan 1, 2017

How the Australasian and Canadian Codes (VALMIN and CIMVal) approach mineral property valuation is described. Brief comment is also made on the International Valuation Standards CommitteeÆs interest in a global valuation standard for Mineral (Extractive) Industries and the South African SAMREC initiatives to adopt a VALMIN-like Code. The conventional tripartite classification of valuation approaches into those that are Market-based, Income-based and Cost-based is outlined. It is best practice to use as many of these approaches as possible (and as many methods as reasonable in the particular circumstances), given the quantity and quality of the data available on the Mineral Asset (which depends upon the state of development of the mineral property). The use of specific methods must satisfy the basic considerations of logic and reasonableness and the purpose of the valuation. The competence, judgement and repute of the valuer are critical factors, since all valuations are time and circumstance specific. What constitutes æMarket ValueÆ in the different jurisdictions is discussed and definitions are given. Challenges facing the globalisation of a VALMIN-type Code for the international Minerals Industry are the influence of real estate valuers and the US jurisdictional idiosyncrasies. This is mainly due to a fixation on real property rights with a preference for using real estate-like comparative sales techniques (Market Approach) to the exclusion of Income-based approaches; a regulatory reluctance in the US to accept that Resources have considerable value; and the International Accounting Standards BoardÆs preference for Historical, rather than Current Value, accounting.

Jan 1, 2002

By B. Boberg

Annual requirements of uranium to fuel the 441 currently operating nuclear reactors in the world is 170 million pounds U3O8 (65,385 tonnes U). 2005 global production was 108 million pounds (41,595 t U), of which only 2.7 million pounds U3O8 (1,039 t U), was produced from US uranium deposits. US nuclear utilities represent 26% of the global nuclear capacity but only obtain 2.5% of their supply from US uranium mines. Since 2002 annual global production increased from 93 million pounds U3O8, a 15% increase and the US production increased from 2.3 million pounds to 2.7 million pounds, a 17% increase. Reasonably Assured Resources (RAR) of 12,332 million pounds U3O8 (4.7 million t U) are reported from a wide variety of countries and types of uranium deposits. This RAR suggests that there are significant global uranium resources potentially producible at a price of $50 per pound U3O8 ($130 per kg U). Table 1 shows the distribution of global uranium resources. This table, prepared from historic data maintained by the World Nuclear Association, does not include some areas of the world that are currently considered to contain significant resources of uranium such as Mongolia. Table 1 suggests that the United States contains the fourth largest uranium resource in the world with 890 million pounds U3O8, behind Australia, Kazakhstan and Canada in resources that are producible at a price of $50 per pound U3O8 ($130 per kg U). Within the US, the states that demonstrate the greatest amount of uranium resource are Wyoming, New Mexico, Texas and the Four Corners Area of Arizona, Colorado and Utah.

Jan 1, 2007

By M. Bennett, L. Twidwell

Montana Tech has embarked on a coordinated series of studies to delineate the characteristics of the Berkeley Pitlake containing over 36 billion gallons of acidic, metal-contaminated water formed after the cessation of open-pit copper mining in Butte, Montana, USA. The objectives of the overall series of studies are to summarize presently available information and to generate new and needed information to formulate a conceptual environmental model for the pitlake and to provide characterization data for the development of advanced treatment technologies. In this presentation, the chemistry of the Berkeley Pitlake water is partially reviewed. It is known that the pitlake consists of two distinct layers of water referred to as surface and deep water. Samples of deep water were collected and placed in a 12-ft high and 6-inch diameter column and exposed to different wavelengths of UV radiation as well as atmospheric conditions. Measurements of pH, redox potential (EH), dissolved O2, turbidity, conductivity, temperature, and elemental composition show that the water reacts differently and indicates that the diurnal effects of sunlight likely play a major non-biological role in its chemistry. Resulting technology could be useful for developing an alternative to treating acid-rock drainage.

Jan 1, 2007

By V. Bush, T. G. Killingsworth, E. P. Ruffel

Effective and sustained corporate energy management programs are becoming a necessity for energy users as electricity deregulation laws are enacted on a state-by-state basis across the country and environmental regulations pertaining to emissions become more prevalent. The “Total Energy Asset Management” (TEAM) approach has been developed to assist energy end users with the development and implementation of corporate energy management programs designed to reduce energy risks and increase energy cost savings. This paper highlights the ways in which this approach can be applied to the mining industry while minimizing initial program implementation costs and increasing potential program benefits. Nearly the entire mining industry has become very focused on identifying opportunities to reduce costs per unit of yield. The industry as a whole has increasingly faced pricing pressures in large part due to the effects of global competition. The result of international marketplace participation and the emergence of higher efficiency recovery techniques have resulted in flat or even decreased prices for mining products. Thus, opportunities to reduce costs are actually opportunities to gain a competitive edge over similar mining operations. Due to the energy-intensive nature of many mining operations, the costs associated with energy are often a substantial percentage of operating costs. Therefore, it becomes very important to develop the corporate mentality that energy is an asset whose use should be optimized globally. In addition to the cost benefits of the TEAM approach, other benefits may occur such as reductions in facility greenhouse gas emissions.

Jan 1, 2002

By Robert Martin, Brian W. Stump, David P. Anderson

2We use field measurements to quantify physical processes that accompany different types of mining explosions. The data sets collected include three-component ground motion, acoustic, video and high speed film, three dimensional topography, geological and geophysical properties, design blast pattern and timing, and velocity of detonation in the explosive for individual borehole detonation times. The explosions include simple single-fired contained explosions, ones designed to bulk and fracture material and those that cast material. Our goal is a physical understanding of these sources for the purposes of optimizing blasting practices.

Jan 1, 1998

By M. D. Lackey

The "Art" of Big Hole Drilling has been in a continual state of evolution at the Nevada Test Site since the start of underground testing in 1961. Emplacement holes for nuclear devices are still being drilled by the rotary drilling process, but almost all the hardware and systems have undergone many changes during the intervening years. The current design of bits, cutters, and other big hole drilling hardware results from contributions of manufacturers and Test Site personnel. The dual string, air lift, reverse circulation system was developed at the Test Site. Necessity was really the Mother of this invention, but this circulation system is worthy of consideration under almost any condition. Drill rigs for Big Hole drilling are usually adaptations of large Oil Well drill rigs with minor modifications required to handle the big bits and drilling assemblies. Steel remains the favorite shaft lining material, but a lot of thought is being given to concrete linings, especially precast concrete.

Jan 1, 1983

By H. Warren Newcomen

Assessments of the stability performance of open pit highwalls have traditionally been based on consideration of surface movement rates. Although generally accepted in industry, this approach presents challenges for establishing appropriate threshold values to allow for safe mining operations and does not address the issue of total strain. Surface movement monitoring data from a limited number of open pit mining operations in North and South America has been evaluated in terms of highwall strain, rock mass quality and inferred mechanism of instability. Threshold strain levels for key stages of highwall stability proposed from previous work have been reviewed and are generally endorsed based on evaluation of additional data. An empirical highwall strain criteria for the assessment of highwall stability performance is postulated based on the observed trends in highwall strain data from the case histories presented.

May 1, 2004

By Jonathan Peck, Doug Pollitt, Malcolm Scoble

Over the past 5 years the Department of Mining and Metallurgical Engineering, McGill University, has been involved in the performance monitoring of both percussive and rotary drills. Studies conducted in open pit coal and iron ore mines using microprocessor-based research and commercially available instrumentation resulted in the monitoring of at least 6 performance parameters while drilling vertical production blastholes.

Jan 1, 1991

By C. O. Karacan, S. J. Schatzel, W. P. Diamond

In coal mining, longwall mining is a preferred method to maximize production by extracting large blocks of coal that have been outlined with a set of development entries. In U.S. mines, longwall panels are typically 305 m (1,000ft) wide (with a continual trend towards even wider panels), and usually over 3,050 m (10,000ft) in length. The increasing size of longwall panels, while helping to increase coal production, may also increase methane emissions due to the exposure of the mining environment to a larger area of fractured, gas-bearing strata. Thus, understanding the impact of increased panel widths on methane emissions, and designing gob gas ventholes and bleeder systems accordingly, can enhance the safety of the underground workforce by reducing their exposure to potentially explosive accumulations of methane/air mixtures. As part of its mine safety research program, NIOSH’s Pittsburgh Research Laboratory has initiated a reservoir modeling effort to better understand the interaction of the various geotechnical factors influencing gas flow within and to the underground longwall mining environment. A focus of this modeling effort has been 1) the prediction of the incremental amount of methane emissions to be expected due to increasing longwall panel widths, and 2) optimizing gob gas venthole completion practices to capture more of the gas in the subsided strata above longwall panels before it can enter the ventilation system of the underground workplace. The history matching phase of the study has been carried out on a 381-m (1,250ft) wide panel in the Pittsburgh Coalbed. Simulations have also been completed for a 442 m (1,450ft) wide panel to estimate the incremental increase in methane emissions and the performance of current gob gas venthole placement configurations. Additional venthole placement configurations were simulated to investigate options for optimizing methane capture from the subsided strata above the wider longwall panel.

By S. Hunt, D. de Vries

Kansanshi Copper Smelter began operation in March 2015. The smelter features a single Isasmelt furnace for smelting, one 6-in-line electric furnace for matte-settling and slag-cleaning duties, four Peirce- Smith converters and two rotary anode furnaces. A 1,450 t/day oxygen plant and a 4,085 t/day sulphuric acid plant are included in the smelter operations. This paper gives an overview of the operational performance to date with summary data for each smelter section. Challenges such as an unforeseen refractory failure in the Isasmelt furnace in 2016 are discussed. Design improvements around the electric furnace are mentioned. Plans for potential future improvements are put into context. A consistent focus on operations, maintenance and continuous improvement has seen the smelter easily achieve its nameplate capacity of 1.2 million tonnes per annum of copper concentrate throughput. The smelter now operates consistently at a concentrate throughput rate of 1.38 million tonnes per annum of copper concentrate. INTRODUCTION The smelter was commissioned in March 2015. Design and commissioning of the smelter have been discussed by de Vries, Hunt, Hanschar and Louie (2016). The smelter rapidly ramped up to achieve nameplate production (1.2 million tonnes per year concentrate) and in 2018 operated consistently at the rate of 1.38 million tonnes per year concentrate. This paper presents major operational data for each section of the plant and describes significant events and improvements during the first four years of operation. The smelter flowsheet is shown in Figure 1.

Jan 1, 2019

By Donald Hulse

"Mining has been a source of controversy for at least 500 years. “Since there has always been the greatest disagreement amongst men concerning metals and mining, some praising, others utterly condemning them…” (Agricola, 1556). In 2016, it is widely recognized that mineral resources and reserves must give due regard to the social license in order to operate.“Most commonly, the social license to operate (SLO) is understood to refer to ‘the ongoing acceptance and approval of a [project] by local community members and other stakeholders that can affect its profitability’ (Moffat, 2014).” “Social License to Operate has gained traction, in part, because it is also a concept which – while remaining poorly, technically defined – is generally easily and widely understood by community stakeholders (Bice, 2014).”A generation ago we learned that mining is based on a stable platform supported by three pillars, geology, mining and metallurgy. The three-legged stool is a very stable structure (Fig. 1).In 2016, it seems that we have added some other legs to the stool (Fig 2). The Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (JORC Code) addresses “social, and governmental factors…” (JORC 2012), and refers specifically to social license in Section 4 of the Report Template “Estimation and Reporting of Ore Reserves.”The Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Guidelines refer to “environmental, legal and social data…(CIM 2003).”Compared to these, the 2014 SME Guide is positively verbose stating “a discussion of any potential social or community related requirements and plans for the project and the status of any negotiations or agreements with local communities,” (SME 2014) although in all cases the scope of this disclosure is left at the discretion of the competent person.When there are more than three legs on the stool, it is imperative that all legs be constructed exactly to the design. Any one or more legs that are out of alignment will cause the stool to wobble.Engineers are trained to create designs to meet specifications. Loads can be estimated, forces calculated and cost studies completed that will lead to, not only a stable design, but the most efficient design that meets the specifications."

Jan 1, 2015

SME's Annual Membership Report - 1961 Membership Directory

Jan 7, 1961

By J. A. Bakken, M. T. Jonsson, G. A. Saevarsdottir, H. Palsson

The electrodes of a Submerged Arc Furnaces carry a high current and are subject to enormous stresses caused by both the electric arc itself, and the current distribution within the electrode. The external effect of the arc on the electrode is treated in a different paper at this conference, The purpose of this paper is to analyze the thermal effects of ohmic heating within the electrode at the arc attachment on the carbon based electrode, using data for Søderberg electrodes. The thermal conditions are then used to examine stress conditions in the vicinity of an arc. Two types of models of an electrode are presented in the paper. The first type is an accurate finite element model, based on both two and three dimensional elements and the second type is an one dimensional model, providing better insight into the problem. For the second type, a spherical model of thermal conditions in a semi-infinite solid has been developed. Results show that the electrode surface is heated quickly up to a maximum temperature and for a specific test case, the surface can only withstand the load for about 10 seconds. Also, the thermal stresses on the surface are very high which will increase erosion on the surface in addition to normal evaporation.

Jan 1, 2007

The Bureau of Mines is active in programs pertaining to solid waste disposal and land reclamation. Nine reclamation projects of mining companies and six projects of the Commonwealth of Pennsylvania were investigated to provide information on the procedures, costs, and results obtained from reclamation projects of bituminous coal-waste disposal areas. Refuse disposal costs of mining companies ranged from 9 to 28 cents per ton-mile, and quantities disposed of ranged from 600 to 4,500 tons per day. Spreading and compacting the refuse at the dump site ranged from 3 to 20 cents per ton. Cost of covering with soil and planting ranged from $750 to $1,646 per acre. Total costs of reclamation for the Pennsylvania projects ranged from about $1,800 to more than $15,000 per acre. Refuse preparation costs ranged from $772 to $5,550 per acre. Soil covering and planting costs ranged from $1,083 to $5,086 per acre. The best results were obtained by soil preparation and conditioning prior to planting. The type and depth of soil and effect of climate were also factors.

Jan 1, 1973

By Leonardo Massone

The p-y method is one of the most popular methods in pile design and has been calibrated for various boundary conditions using numerical and experimental studies during recent years. Most studies on reinforced concrete (RC) piles have included the impact of flexural nonlinearity, (e.g. nonlinear moment?curvature relations) but not considered associated pile shear deformations when deriving p-y curves from field data. Common p-y curves may be better applicable for piles with flexure dominated failures (e.g. piles with free- head boundary conditions). For piles with fixed head boundaries (i.e. rotation restrained piles) shear deformations could be of significant influence. To study this problem, a coupled shear flexure interaction model for axial-bending-shear behavior coded in OpenSees was applied to a 0.61 m (2 ft) diameter flagpole and a 0.61m (2 ft) diameter fixed head pile specimen to investigate the possible influence of shear deformations to the overall pile responses. The surrounding soil was represented by p-y curves derived from prior large scale testing on piles with similar boundary conditions. Analysis results show that for flagpole piles, shear forces and shear deformations were insignificant. Considerable contributions of pile shear displacements and forces were observed for the fixed head pile, with shear displacements contributing up to 40% of the total pile displacement. Results suggest that nonlinear shear deformations for reinforced concrete piles should be considered for fixed-head or similar conditions, and that currently used p-y curves may underestimate the actual lateral pile displacement and possibly lead to unsafe design for the particular boundary condition.

Jan 1, 2012

By M. van Elp, R. Saitua Nistal, P. J. M. Groot

Demand for construction raw materials depends on investment in housing, other buildings and infrastructure. The provision of these materials requires early knowledge of future trends in construction investment. By using scenarios possible future developments and bandwidths can be explored. Policy makers in government organisations as well as in the private sector can base their policy decisions upon these insights. In this paper we discuss the case of sand and gravel in the Netherlands. We will show that, depending on the future role of government and the degree of internationalisation, the long term demand for construction raw materials will strongly diverge. Nevertheless there are some common developments such as a decreasing population growth, a smaller share of the labour force in total population and a growing wealth. In different scenarios we will encounter different conditions for minerals provision and for sustainable development.

Jan 1, 2011

By M. Savich

A graphical method has been developed for the evaluation of the U.S. Occupational Safety and Health Act Noise Exposure Index and the Equivalent Continuous Sound Level. The method makes use of a noise survey form and a mechanical integrator with two sliders, and is less tedious and susceptible to error than alternative methods. The graphical method is adaptable to various codes for noise exposure and may be used with any instrument that measures noise level. One example of its application to a practical situation in a Canadian mine is given to demonstrate the procedure .

Jan 1, 1978

The richer, shallower sapphire deposits of the New England region of New South Wales which have been traditionally mined by the small miner are almost worked out. Larger mining and exploration companies are replacing the small miner and exploring for the primary source of sapphire or lower grade alluvial deposits.   Although in recent years considerable exploration effort has been directed at locating the primary source, commercial exploitation of sapphire is still restricted to the working of alluvial deposits.   If the Australian industry is to compete against Asian and African producers it must use cost effective exploration, mining) processing and marketing methods.

Jan 1, 1990

By G. Howell, J. Wates, A. Coetzee, C. J. MacRobert

The Global Industry Standard on Tailings Management (GISTM) requires mining companies to make four key appointments as part of their tailings management structure. These four positions are an Accountable Executive with policymaking responsibilities, a Responsible Tailings Facility Engineer with operational responsibility, an Engineer of Record to ensure facilities are designed, operated, and closed safely, and an Independent Tailings Review Board to assess safety drivers regularly. Little guidance on the traits of these individuals is available in a South African context. Consequently, the tailings community of practice was surveyed to develop a table of ideal competencies and establish the flexibility in meeting these traits.

Jun 2, 2022